1. Field of the Invention
The present invention relates to facility design technology, particularly for a system, a computer implemented method and a computer program product for designing a utility facility, based on utility consumption of a production line.
2. Description of the Related Art
In the case of the related art, quantities of utilities, such as electricity and gases, which are used by tools for the production of products, are calculated by multiplying utility specification for usage of each tool, by corresponding coefficients (load factors), respectively. As is often the case, the utility specifications of each of the tools demand utilities larger than utilities actually consumed during operation. As a result, the total capacity for a designed utility facility is larger than the total quantity of utilities consumed by each of the tools included in the production line during operation.
As is often the case, the load factors are determined based on the experience of persons in charge of facility design. Usually, load factors tend to be surplus so that undersupply of respective utilities does not occur. The quantities of utility demanded, which have been calculated with surplus load factors, respectively, largely deviate from quantities of utilities consumed during actual operation. As a result, a utility facility with an unnecessarily large size is designed.
A utility facility once included in the factory is not capable of low capacity operation by reducing quantities of utilities to be supplied. For such reason, regardless of the quantities of utilities consumed by each of the tools and the number of products processed during actual operation, the utility facility continues operating with the designed quantities of utilities. Accordingly, running costs are kept almost constant. In a case where large utility specifications for usage are calculated, compared with utilities consumed during actual operations, the excessive capacity of the utility facility is large. For example, a production line for wafers, each with a diameter of 300 mm, indicates extremely large utility specifications, and the excessive capacity of a utility would be larger than ever. In this case, running costs become increased, and there also exists a problem from the viewpoint of energy savings when actual consumption is less than designed capacity.
The reduction of quantities has been examined for the quantity of utilities consumed by each of the tools included in the production line. However, the reduction of the quantities of utilities consumed by each of the tools and in the facility is within an excessive surplus set during the design of the utility facility. Thus, it is difficult to estimate how much effect will be achieved by reducing utilities in each of the tools. As a result, the reduced quantities of the utility have not been employed in the design stage of the utility facility.
As for an example similar to the foregoing explanation, the following method has been proposed. In such method, quantities of utilities consumed by each of the tools are calculated by a simulation using a virtual production line, and quantities of utilities to be supplied to a production line are determined. While the foregoing method can be applied to a production line already manufacturing products, the method cannot be applied to a production line in a production planning phase. Moreover, in the case of the foregoing method, a state in which each of the tools is in operation and a state in which the tools are in standby is not discriminated from each other. This makes it impossible to estimate accurate quantities of utilities to be respectively supplied.